Short answers, pulled from the story.
Edward Seymour, 1st Duke of Somerset, was an English nobleman born around 1500 who served as Lord Protector of England from 1547 to 1549 during the minority of his nephew King Edward VI. He was the eldest surviving brother of Queen Jane Seymour, the third wife of Henry VIII. He was executed on the 22nd of January 1552.
On the 4th of February 1547, six days after Henry VIII's death, thirteen of the sixteen executors named in Henry's will agreed to invest Seymour with the office of Lord Protector, despite the will making no provision for a single Protector. Seymour had secured key support in advance, including deals with William Paget and Sir Anthony Browne. He subsequently obtained letters patent in March 1547 granting him near-monarchical authority over the Privy Council.
The Prayer Book Rebellion of 1549 arose mainly from the imposition of church services in English under the first Act of Uniformity. The uprising centered in Devon and Cornwall, where many people spoke Cornish and rejected the new English liturgy. It was one of two major revolts that year requiring large-scale military intervention to suppress.
The Battle of Pinkie Cleugh took place on the 10th of September 1547, when Seymour led an English army into Scotland and won a decisive victory. The campaign was a continuation of Henry VIII's strategy to force a dynastic union between England and Scotland through conquest. After the battle, Seymour established garrisons across the Scottish Lowlands as far north as Dundee, though the strategy ultimately failed when Scotland allied with France.
Thomas Seymour was arrested in January 1549 on charges including embezzlement at the Bristol mint and scheming to marry Princess Elizabeth without council approval. Because evidence of treason was insufficient for a trial, he was condemned through an Act of Attainder and beheaded on the 20th of March 1549. King Edward VI himself testified about pocket money Thomas had secretly supplied to him.
Historians' views have shifted sharply over time. Early 20th-century scholar A. F. Pollard and Edward VI's 1960s biographer W. K. Jordan portrayed Somerset as a champion of the common people against the landowning class. From the mid-1970s onward, M. L. Bush and Dale Hoak led a reassessment that depicted him as arrogant and lacking the political and administrative skills the Tudor state required.